There is a vehicle seat of a type having a retractor of a seat belt internally mounted in a seat back. In this type of vehicle seat, the retractor is mounted to a rear frame, which serves as a frame of the seat back, by a mounting bracket. In a configuration disclosed in JP-A-2002-283892, in order to ensure the rigidity of the rear frame, the rear frame is configured to have a rectangular frame body and is provided with the mounting bracket for mounting the retractor on a lower corner part of the frame body.
In the configuration disclosed in JP-A-2002-283892, after shaping the rear frame into a rectangular frame shape, the bracket is mounted on the rear frame. That is to say, the strength and rigidity of the vehicle seat as a frame is ensured solely by the rear frame, and the bracket is in place only for mounting the retractor on the rear frame. Thus, the structure of the rear frame is the same as that of the vehicle seat of a type without a retractor, and as the mounting of the bracket does not help to omit any part of the vehicle seat, the vehicle seat may become heavier in weight.